Jonathan Corbet <corbet@xxxxxxx> wrote on 01/15/2019 08:08:54 PM: > From: Jonathan Corbet <corbet@xxxxxxx> > To: "Joel Nider" <JOELN@xxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>, Doug Ledford <dledford@xxxxxxxxxx>, > Jason Gunthorpe <jgg@xxxxxxxx>, Leon Romanovsky <leon@xxxxxxxxxx>, linux- > doc@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, Mike Rapoport <rppt@xxxxxxxxxxxxx> > Date: 01/15/2019 08:09 PM > Subject: Re: [PATCH v2 2/2] docs-rst: userspace: update verbs API details > > On Tue, 15 Jan 2019 18:29:59 +0200 > "Joel Nider" <JOELN@xxxxxxxxxx> wrote: > > > > I think this is a horrible direction to take. The current document is > > > clearly for _users_. All this documentation you've added is for kernel > > > hackers. It needs to go in a different file, or not be added at all. > > > > > Hmm, that's a bit heavy-handed in my opinion. If you look at what is > > currently under "Userspace API", there are a total of 4 files - not > > exactly what I would call comprehensive documentation of the Linux kernel > > interface. > > One has to start somewhere - I'm glad to see you adding to it. > > > So the option of not adding more documentation simply because > > it is in the wrong section seems a bit defeatist (I think we can all agree > > more kernel docs is a good thing). So let's assume for the moment that it > > _should_ be added, and that we are discussing _where_. > > I think we definitely want to add it. > > > Yes, the document I > > am modifying has a bit of a mash of pure userspace API - functions and > > details that application developers must know - and the lower level > > details that are more useful for someone who wishes to extend this > > interface. The existing documentation (specifically unshare) also suffers > > from the same problem. There is a section (7) called "Low Level Design" > > which documents very much the same level of detail as the Infiniband doc, > > so this seems to be at least consistent. > > I think there is a deeper issue - as an application developer, I would > > only look at this kernel documentation as a last resort. #1 is the 'man' > > pages, #2 is web search for an example (I know for many it's the other way > > around). So who really looks at this documentation? I say the vast > > majority is kernel hackers. So yes, this is about the user-facing API, but > > not from the application writer's perspective - it should be about how to > > create a consistent API for users, from the kernel hacker's perspective. > > The intent behind the user-space API manual is to document the user-space > API; it's meant to be read by people writing applications and such. > Perhaps they find it with a web search, but it will be there for them, one > hopes, when they want it. So is the intent then to duplicate what is already in 'man'? Why would we want 2 different locations for basically the same information? Wouldn't it make more sense to just put these few details into appropriate 'man' pages? > The project of reworking the kernel documentation to be more comprehensive > and more focused on its readers, rather than, as Rob Landley once put it, > "a gigantic mess, currently organized based on where random passers-by put > things down last" is still in an early stage. But that doesn't mean that > we shouldn't try to always move in the right direction. It looks like I misunderstood the purpose of the "userspace API" section then. So is there a section that is meant for a guide on how to write an interface function? > So I agree with > Willy that this particular text is better suited to the driver-API > manual. Even if a bare bit of information on its own there for now, it's > a starting place. Can I ask you to do that, please? OK, just to be clear - you are asking me to leave the original file as-is (well, after .rst conversion) but move it to the new location (Documentation/userspace-api), and put my new content into a new file in the old location (Documentation/infiniband)? > Thanks, > > jon >
